[R] RE: [Rd] too many arguments in foreign function call
Prof Brian D Ripley
ripley at stats.ox.ac.uk
Mon Jul 16 20:23:52 CEST 2001
On Mon, 16 Jul 2001, Warnes, Gregory R wrote:
> Duncan Murdoch <murdoch at stats.uwo.ca> wrote:
> > Gregory R. Warnes <gregory_r_warnes at groton.pfizer.com> wrote
> > >
> > >I would like to create an R package that will depend on
> > the ability to use
> > >more than 65 parameters. Would it be reasonable to expect
> > this patch (or
> > >something equivalent) to be part of , say R > 1.3.1 ?
> > People are slow to upgrade, so you might be better off in the short
> > run to somehow reduce the number of parameters below 65.
> > For example,
> > write a wrapper function that groups a number of scalar parameters
> > into one vector.
> Actually, the whole point of the patch was to get out of this. I want to
> keep the code as close to what was written by the original author and as
> simple as possible...
Sorry, but I don't see that. You want to write the wrapper in R? Why is
it not as simple to write it in C? I really don't see the need to remove
the limitation in R (or even to have it as high as 65) since R now has
.External() which allows an unlimited list of arguments to be passed to C
code. I can't believe that the natural R representation is 85 separate
objects, so the natural way looks like a C wrapper translating between R
objects and Fortran pointers. You can even copy selectively.
The argument is that new code should probably be using .Call (if S
compatibility is relevant) or .External rather than .C, at least provided
that a C wrapper is feasible. Those interfaces seem very much under-used.
(Including by me, for S3-compatibility reasons.)
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272860 (secr)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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